Bullet support

collision/types.go

@@ -14,6 +14,7 @@ type ObjectType int
 const (
 	Hero ObjectType = 1 << iota
 	Zombie
+	Bullet
 )
 
 type Collidable interface {

collision/world.go

@@ -18,7 +18,10 @@ func (w *World) RemoveEntity(e Collidable) {
 
 func (w *World) NotifyAboutCollisions() {
 	for i, entity := range w.Entities {
-		for _, other := range w.Entities[i+1:] {
+		for j, other := range w.Entities {
+			if i == j {
+				continue
+			}
 			if entity.CollisionShape().Overlaps(other.CollisionShape()) {
 				entity.HandleCollisionEvent(other)
 				other.HandleCollisionEvent(entity)